diff --git a/IPython/config/application.py b/IPython/config/application.py
index 264d379..3b848c3 100644
--- a/IPython/config/application.py
+++ b/IPython/config/application.py
@@ -14,7 +14,7 @@ import sys
 from copy import deepcopy
 from collections import defaultdict
 
-from IPython.external.decorator import decorator
+from decorator import decorator
 
 from IPython.config.configurable import SingletonConfigurable
 from IPython.config.loader import (
diff --git a/IPython/core/formatters.py b/IPython/core/formatters.py
index f5126c9..3c622cf 100644
--- a/IPython/core/formatters.py
+++ b/IPython/core/formatters.py
@@ -17,7 +17,7 @@ import sys
 import traceback
 import warnings
 
-from IPython.external.decorator import decorator
+from decorator import decorator
 
 from IPython.config.configurable import Configurable
 from IPython.core.getipython import get_ipython
diff --git a/IPython/core/history.py b/IPython/core/history.py
index c615ad8..7c1076c 100644
--- a/IPython/core/history.py
+++ b/IPython/core/history.py
@@ -28,7 +28,7 @@ import threading
 
 # Our own packages
 from IPython.config.configurable import Configurable
-from IPython.external.decorator import decorator
+from decorator import decorator
 from IPython.utils.decorators import undoc
 from IPython.utils.path import locate_profile
 from IPython.utils import py3compat
diff --git a/IPython/core/magic.py b/IPython/core/magic.py
index f085717..7d8b981 100644
--- a/IPython/core/magic.py
+++ b/IPython/core/magic.py
@@ -27,7 +27,7 @@ from IPython.config.configurable import Configurable
 from IPython.core import oinspect
 from IPython.core.error import UsageError
 from IPython.core.inputsplitter import ESC_MAGIC, ESC_MAGIC2
-from IPython.external.decorator import decorator
+from decorator import decorator
 from IPython.utils.ipstruct import Struct
 from IPython.utils.process import arg_split
 from IPython.utils.py3compat import string_types, iteritems
diff --git a/IPython/core/tests/test_oinspect.py b/IPython/core/tests/test_oinspect.py
index 1d7f7bc..a0d0f55 100644
--- a/IPython/core/tests/test_oinspect.py
+++ b/IPython/core/tests/test_oinspect.py
@@ -26,7 +26,7 @@ from IPython.core.magic import (Magics, magics_class, line_magic,
                                 cell_magic, line_cell_magic,
                                 register_line_magic, register_cell_magic,
                                 register_line_cell_magic)
-from IPython.external.decorator import decorator
+from decorator import decorator
 from IPython.testing.decorators import skipif
 from IPython.testing.tools import AssertPrints
 from IPython.utils.path import compress_user
diff --git a/IPython/external/decorator/__init__.py b/IPython/external/decorator/__init__.py
deleted file mode 100644
index d0e95b4..0000000
--- a/IPython/external/decorator/__init__.py
+++ /dev/null
@@ -1,4 +0,0 @@
-try:
-    from decorator import *
-except ImportError:
-    from ._decorator import *
diff --git a/IPython/external/decorator/_decorator.py b/IPython/external/decorator/_decorator.py
deleted file mode 100644
index ef56922..0000000
--- a/IPython/external/decorator/_decorator.py
+++ /dev/null
@@ -1,229 +0,0 @@
-##########################     LICENCE     ###############################
-
-# Copyright (c) 2005-2012, Michele Simionato
-# All rights reserved.
-
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-
-#   Redistributions of source code must retain the above copyright
-#   notice, this list of conditions and the following disclaimer.
-#   Redistributions in bytecode form must reproduce the above copyright
-#   notice, this list of conditions and the following disclaimer in
-#   the documentation and/or other materials provided with the
-#   distribution.
-
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
-# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
-# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
-# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
-# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
-# TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
-# USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
-# DAMAGE.
-
-"""
-Decorator module, see http://pypi.python.org/pypi/decorator
-for the documentation.
-
-NOTE: this is an IPython-patched version to work on IronPython. See
-      FIXED comment below.
-"""
-from __future__ import print_function
-
-__version__ = '3.3.3'
-
-__all__ = ["decorator", "FunctionMaker", "partial"]
-
-import sys, re, inspect
-
-try:
-    from functools import partial
-except ImportError: # for Python version < 2.5
-    class partial(object):
-        "A simple replacement of functools.partial"
-        def __init__(self, func, *args, **kw):
-            self.func = func
-            self.args = args
-            self.keywords = kw
-        def __call__(self, *otherargs, **otherkw):
-            kw = self.keywords.copy()
-            kw.update(otherkw)
-            return self.func(*(self.args + otherargs), **kw)
-
-if sys.version >= '3':
-    from inspect import getfullargspec
-else:
-    class getfullargspec(object):
-        "A quick and dirty replacement for getfullargspec for Python 2.X"
-        def __init__(self, f):
-            self.args, self.varargs, self.varkw, self.defaults = \
-                inspect.getargspec(f)
-            self.kwonlyargs = []
-            self.kwonlydefaults = None
-        def __iter__(self):
-            yield self.args
-            yield self.varargs
-            yield self.varkw
-            yield self.defaults
-
-DEF = re.compile('\s*def\s*([_\w][_\w\d]*)\s*\(')
-
-# basic functionality
-class FunctionMaker(object):
-    """
-    An object with the ability to create functions with a given signature.
-    It has attributes name, doc, module, signature, defaults, dict and
-    methods update and make.
-    """
-    def __init__(self, func=None, name=None, signature=None,
-                 defaults=None, doc=None, module=None, funcdict=None):
-        self.shortsignature = signature
-        if func:
-            # func can be a class or a callable, but not an instance method
-            self.name = func.__name__
-            if self.name == '<lambda>': # small hack for lambda functions
-                self.name = '_lambda_'
-            self.doc = func.__doc__
-            self.module = func.__module__
-            if inspect.isfunction(func):
-                argspec = getfullargspec(func)
-                self.annotations = getattr(func, '__annotations__', {})
-                for a in ('args', 'varargs', 'varkw', 'defaults', 'kwonlyargs',
-                          'kwonlydefaults'):
-                    setattr(self, a, getattr(argspec, a))
-                for i, arg in enumerate(self.args):
-                    setattr(self, 'arg%d' % i, arg)
-                if sys.version < '3': # easy way
-                    self.shortsignature = self.signature = \
-                        inspect.formatargspec(
-                        formatvalue=lambda val: "", *argspec)[1:-1]
-                else: # Python 3 way
-                    self.signature = self.shortsignature = ', '.join(self.args)
-                    if self.varargs:
-                        self.signature += ', *' + self.varargs
-                        self.shortsignature += ', *' + self.varargs
-                    if self.kwonlyargs:
-                        for a in self.kwonlyargs:
-                            self.signature += ', %s=None' % a
-                            self.shortsignature += ', %s=%s' % (a, a)
-                    if self.varkw:
-                        self.signature += ', **' + self.varkw
-                        self.shortsignature += ', **' + self.varkw
-                self.dict = func.__dict__.copy()
-        # func=None happens when decorating a caller
-        if name:
-            self.name = name
-        if signature is not None:
-            self.signature = signature
-        if defaults:
-            self.defaults = defaults
-        if doc:
-            self.doc = doc
-        if module:
-            self.module = module
-        if funcdict:
-            self.dict = funcdict
-        # check existence required attributes
-        assert hasattr(self, 'name')
-        if not hasattr(self, 'signature'):
-            raise TypeError('You are decorating a non function: %s' % func)
-
-    def update(self, func, **kw):
-        "Update the signature of func with the data in self"
-        func.__name__ = self.name
-        func.__doc__ = getattr(self, 'doc', None)
-        func.__dict__ = getattr(self, 'dict', {})
-        func.__defaults__ = getattr(self, 'defaults', ())
-        func.__kwdefaults__ = getattr(self, 'kwonlydefaults', None)
-        func.__annotations__ = getattr(self, 'annotations', None)
-        # FIXED: The following is try/excepted in IPython to work 
-        # with IronPython.
-        try:
-            callermodule = sys._getframe(3).f_globals.get('__name__', '?')
-        except AttributeError: # IronPython _getframe only exists with FullFrames
-            callermodule = '?'
-        func.__module__ = getattr(self, 'module', callermodule)
-        func.__dict__.update(kw)
-
-    def make(self, src_templ, evaldict=None, addsource=False, **attrs):
-        "Make a new function from a given template and update the signature"
-        src = src_templ % vars(self) # expand name and signature
-        evaldict = evaldict or {}
-        mo = DEF.match(src)
-        if mo is None:
-            raise SyntaxError('not a valid function template\n%s' % src)
-        name = mo.group(1) # extract the function name
-        names = set([name] + [arg.strip(' *') for arg in
-                             self.shortsignature.split(',')])
-        for n in names:
-            if n in ('_func_', '_call_'):
-                raise NameError('%s is overridden in\n%s' % (n, src))
-        if not src.endswith('\n'): # add a newline just for safety
-            src += '\n' # this is needed in old versions of Python
-        try:
-            code = compile(src, '<string>', 'single')
-            # print >> sys.stderr, 'Compiling %s' % src
-            exec(code, evaldict)
-        except:
-            print('Error in generated code:', file=sys.stderr)
-            print(src, file=sys.stderr)
-            raise
-        func = evaldict[name]
-        if addsource:
-            attrs['__source__'] = src
-        self.update(func, **attrs)
-        return func
-
-    @classmethod
-    def create(cls, obj, body, evaldict, defaults=None,
-               doc=None, module=None, addsource=True, **attrs):
-        """
-        Create a function from the strings name, signature and body.
-        evaldict is the evaluation dictionary. If addsource is true an attribute
-        __source__ is added to the result. The attributes attrs are added,
-        if any.
-        """
-        if isinstance(obj, str): # "name(signature)"
-            name, rest = obj.strip().split('(', 1)
-            signature = rest[:-1] #strip a right parens
-            func = None
-        else: # a function
-            name = None
-            signature = None
-            func = obj
-        self = cls(func, name, signature, defaults, doc, module)
-        ibody = '\n'.join('    ' + line for line in body.splitlines())
-        return self.make('def %(name)s(%(signature)s):\n' + ibody,
-                        evaldict, addsource, **attrs)
-
-def decorator(caller, func=None):
-    """
-    decorator(caller) converts a caller function into a decorator;
-    decorator(caller, func) decorates a function using a caller.
-    """
-    if func is not None: # returns a decorated function
-        evaldict = func.__globals__.copy()
-        evaldict['_call_'] = caller
-        evaldict['_func_'] = func
-        return FunctionMaker.create(
-            func, "return _call_(_func_, %(shortsignature)s)",
-            evaldict, undecorated=func, __wrapped__=func)
-    else: # returns a decorator
-        if isinstance(caller, partial):
-            return partial(decorator, caller)
-        # otherwise assume caller is a function
-        first = inspect.getargspec(caller)[0][0] # first arg
-        evaldict = caller.__globals__.copy()
-        evaldict['_call_'] = caller
-        evaldict['decorator'] = decorator
-        return FunctionMaker.create(
-            '%s(%s)' % (caller.__name__, first),
-            'return decorator(_call_, %s)' % first,
-            evaldict, undecorated=caller, __wrapped__=caller,
-            doc=caller.__doc__, module=caller.__module__)
diff --git a/IPython/parallel/client/asyncresult.py b/IPython/parallel/client/asyncresult.py
index 7c45a70..340398b 100644
--- a/IPython/parallel/client/asyncresult.py
+++ b/IPython/parallel/client/asyncresult.py
@@ -12,7 +12,7 @@ from datetime import datetime
 from zmq import MessageTracker
 
 from IPython.core.display import clear_output, display, display_pretty
-from IPython.external.decorator import decorator
+from decorator import decorator
 from IPython.parallel import error
 from IPython.utils.py3compat import string_types
 
diff --git a/IPython/parallel/client/client.py b/IPython/parallel/client/client.py
index 44c6d1a..ea17490 100644
--- a/IPython/parallel/client/client.py
+++ b/IPython/parallel/client/client.py
@@ -31,7 +31,7 @@ from IPython.utils.path import get_ipython_dir, compress_user
 from IPython.utils.py3compat import cast_bytes, string_types, xrange, iteritems
 from IPython.utils.traitlets import (HasTraits, Integer, Instance, Unicode,
                                     Dict, List, Bool, Set, Any)
-from IPython.external.decorator import decorator
+from decorator import decorator
 
 from IPython.parallel import Reference
 from IPython.parallel import error
diff --git a/IPython/parallel/client/remotefunction.py b/IPython/parallel/client/remotefunction.py
index ebf5c3b..4453ff2 100644
--- a/IPython/parallel/client/remotefunction.py
+++ b/IPython/parallel/client/remotefunction.py
@@ -8,7 +8,7 @@ from __future__ import division
 import sys
 import warnings
 
-from IPython.external.decorator import decorator
+from decorator import decorator
 from IPython.testing.skipdoctest import skip_doctest
 
 from . import map as Map
diff --git a/IPython/parallel/client/view.py b/IPython/parallel/client/view.py
index 63f73aa..f6b17f6 100644
--- a/IPython/parallel/client/view.py
+++ b/IPython/parallel/client/view.py
@@ -18,7 +18,7 @@ from IPython.utils import pickleutil
 from IPython.utils.traitlets import (
     HasTraits, Any, Bool, List, Dict, Set, Instance, CFloat, Integer
 )
-from IPython.external.decorator import decorator
+from decorator import decorator
 
 from IPython.parallel import util
 from IPython.parallel.controller.dependency import Dependency, dependent
diff --git a/IPython/parallel/controller/scheduler.py b/IPython/parallel/controller/scheduler.py
index 55cc37f..26589b9 100644
--- a/IPython/parallel/controller/scheduler.py
+++ b/IPython/parallel/controller/scheduler.py
@@ -26,7 +26,7 @@ import zmq
 from zmq.eventloop import ioloop, zmqstream
 
 # local imports
-from IPython.external.decorator import decorator
+from decorator import decorator
 from IPython.config.application import Application
 from IPython.config.loader import Config
 from IPython.utils.traitlets import Instance, Dict, List, Set, Integer, Enum, CBytes
diff --git a/IPython/parallel/tests/clienttest.py b/IPython/parallel/tests/clienttest.py
index 28cd73d..1bf3403 100644
--- a/IPython/parallel/tests/clienttest.py
+++ b/IPython/parallel/tests/clienttest.py
@@ -22,7 +22,7 @@ from nose import SkipTest
 import zmq
 from zmq.tests import BaseZMQTestCase
 
-from IPython.external.decorator import decorator
+from decorator import decorator
 
 from IPython.parallel import error
 from IPython.parallel import Client
diff --git a/IPython/parallel/util.py b/IPython/parallel/util.py
index 870063e..3596edf 100644
--- a/IPython/parallel/util.py
+++ b/IPython/parallel/util.py
@@ -28,7 +28,7 @@ import zmq
 from zmq.log import handlers
 
 from IPython.utils.log import get_logger
-from IPython.external.decorator import decorator
+from decorator import decorator
 
 from IPython.config.application import Application
 from IPython.utils.localinterfaces import localhost, is_public_ip, public_ips
diff --git a/IPython/testing/decorators.py b/IPython/testing/decorators.py
index 9537f11..2014c07 100644
--- a/IPython/testing/decorators.py
+++ b/IPython/testing/decorators.py
@@ -52,7 +52,7 @@ import unittest
 # Third-party imports
 
 # This is Michele Simionato's decorator module, kept verbatim.
-from IPython.external.decorator import decorator
+from decorator import decorator
 
 # Expose the unittest-driven decorators
 from .ipunittest import ipdoctest, ipdocstring
diff --git a/setup.py b/setup.py
index 202d7e0..54638ed 100755
--- a/setup.py
+++ b/setup.py
@@ -269,6 +269,7 @@ extras_require['notebook'].extend(extras_require['nbformat'])
 extras_require['nbconvert'].extend(extras_require['nbformat'])
 
 install_requires = [
+    'decorator',
     'path.py', # required by pickleshare, remove when pickleshare is added here
 ]